With little fanfare, DOE released the consumption portion of the 2012 Commercial Building Energy Consumption Survey (CBECS) a few weeks ago. It is disturbing how little attention this received, since it is only the quantified impact of every commercial building energy efficiency program over the decade! The last survey results were from 2003, and hopefully a lot has happened since then.
Just having the results published is an accomplishment, as many (myself included) worked very hard to make sure the survey continued after a previous version was bungled. A broad thank you is owed to AIA, ACEEE, BOMA, USGBC and all the building industry organizations that threw their weight behind keeping this program alive back in 2010 and 2011.
Maybe even more disturbing than the lack of response to the release is that when I looked to find some thoughtful analysis of the results in comparison to the last survey from 2003, I found nothing! Am I the only one who cares? Come on energy efficiency professionals, where are you? I remember plenty of complaints about benchmarking with old data; where is the celebration? (That’s not completely true, as EPA did send out a blast about their plans to update ENERGY STAR Portfolio Manager scores based on the new data, but still.)
So in an effort to encourage the creation of that thoughtful analysis, I have decided to release a quick and dirty version just to prime the pump. A more thorough effort is needed, to say the least.
All I have done here is take the “Total energy consumption and gross energy intensity for sum of major fuels, 2012” table of the 2012 survey and compare it to the same table from the 2003 survey. A few excel formulas later, here are the differences, in percentage terms. Of course, all rational caveats about drawing conclusions from simple statistics without the context of significance apply, because where there are not that many buildings to survey there may be huge differences in results that are not actually meaningful. (For example, the total floor space built before 1920 "increased" from 2003 to 2012, and that would require time travel.)
How does 2012 compare to 2003 for commercial building energy use:
So the first thing to understand is that the survey looks at the composition of the U.S. commercial building stock as well as energy use, for all fuel types, locations and uses, and then slices and dices the data. This chart shows the percent difference for the sum of all energy use, in site BTUs.
The top line conclusion is that the size of the U.S. commercial building stock increased, but energy use per building stayed the same and energy use per square foot dropped by 11%! Congratulations everyone, job well done!
Yes, but unfortunately the total energy used by the sector, and the associated environmental consequences, increased by 20%. So as a whole, the commercial building sector is using more energy, but using that energy more efficiently. Progress, but not nearly enough.
Digging a little deeper, CBECS shows us where efficiency gains may be happening. First, by building size:
I’ve highlighted the extremes in these columns. The first two columns show the growth by building size, and it occurs across the board. We are building big buildings, but maybe not as many huge, city-block sized buildings.
Interestingly, those giant city-block sized buildings are where much of the energy may have been saved. Buildings over 500,000 square feet do not show an increase in total energy use, like all other sizes. We seem to have not been as successful with energy efficiency in smaller buildings, as is to be expected.
How about by space use?
I can’t venture to guess how we have gone wrong in food service and food sales (never mind what the difference is between them), but we have all certainly done an amazing job in vacant buildings! Hi-fives all around! Joking aside, the results in offices, warehouses, and public buildings are legitimately encouraging. Healthcare looks to be a tremendous challenge moving forward.
And by year of construction? Are older buildings becoming more efficient? Here it is by decade of construction:
Again, time travel is still not real, but those are big savings numbers for our oldest buildings. Hard to say what these numbers mean, but obviously we should be pro-preservation of the character of our cities and towns and pro-energy efficiency. I wonder what the next survey will say about progress in buildings built during the ‘oughts from 2000 to 2010, but initial results are not encouraging.
And what about building location? Here it is by census region and division.
Come on, California, get it together! I think the rest of the country is tired of your lack of enthusiasm for energy efficiency! Good job East North Central (Great Lakes states)! Here’s the census map for those of you unpatriotic Americans who don’t know it by heart.
So in conclusion, good work everybody! Energy efficiency has undeniably improved. Energy use by commercial buildings has also, unfortunately and undeniably, grown. The reality is that we have saved the country a whole lot of money through energy efficiency in the last decade, and certainly done less environmental harm than would have been done over that time period. Energy policy is complicated, and of course the impact depends on the fuel sources as much consumption and demand. Interesting exercise, but can we conclude anything more than that from the breakdowns? Probably not.
Hopefully someone will do a much more thorough and thoughtful analysis of the 2012 CBECS in the coming weeks.